;;; company-clang.el --- company-mode completion backend for Clang -*- lexical-binding: t -*-
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;; Copyright (C) 2009, 2011, 2013-2017 Free Software Foundation, Inc.
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;; Author: Nikolaj Schumacher
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;; This file is part of GNU Emacs.
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;; GNU Emacs is free software: you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation, either version 3 of the License, or
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;; (at your option) any later version.
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;; GNU Emacs is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
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;;; Commentary:
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;;
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;;; Code:
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(require 'company)
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(require 'company-template)
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(require 'cl-lib)
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(defgroup company-clang nil
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"Completion backend for Clang."
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:group 'company)
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(defcustom company-clang-executable
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(executable-find "clang")
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"Location of clang executable."
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:type 'file)
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(defcustom company-clang-begin-after-member-access t
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"When non-nil, automatic completion will start whenever the current
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symbol is preceded by \".\", \"->\" or \"::\", ignoring
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`company-minimum-prefix-length'.
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If `company-begin-commands' is a list, it should include `c-electric-lt-gt'
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and `c-electric-colon', for automatic completion right after \">\" and
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\":\"."
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:type 'boolean)
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(defcustom company-clang-arguments nil
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"Additional arguments to pass to clang when completing.
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Prefix files (-include ...) can be selected with `company-clang-set-prefix'
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or automatically through a custom `company-clang-prefix-guesser'."
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:type '(repeat (string :tag "Argument")))
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(defcustom company-clang-prefix-guesser 'company-clang-guess-prefix
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"A function to determine the prefix file for the current buffer."
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:type '(function :tag "Guesser function" nil))
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(defvar company-clang-modes '(c-mode c++-mode objc-mode)
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"Major modes which clang may complete.")
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(defcustom company-clang-insert-arguments t
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"When non-nil, insert function arguments as a template after completion."
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:type 'boolean
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:package-version '(company . "0.8.0"))
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;; prefix ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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(defvar company-clang--prefix nil)
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(defsubst company-clang--guess-pch-file (file)
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(let ((dir (directory-file-name (file-name-directory file))))
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(when (equal (file-name-nondirectory dir) "Classes")
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(setq dir (file-name-directory dir)))
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(car (directory-files dir t "\\([^.]h\\|[^h]\\).pch\\'" t))))
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(defsubst company-clang--file-substring (file beg end)
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(with-temp-buffer
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(insert-file-contents-literally file nil beg end)
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(buffer-string)))
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(defun company-clang-guess-prefix ()
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"Try to guess the prefix file for the current buffer."
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;; Prefixes seem to be called .pch. Pre-compiled headers do, too.
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;; So we look at the magic number to rule them out.
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(let* ((file (company-clang--guess-pch-file buffer-file-name))
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(magic-number (and file (company-clang--file-substring file 0 4))))
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(unless (member magic-number '("CPCH" "gpch"))
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file)))
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(defun company-clang-set-prefix (&optional prefix)
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"Use PREFIX as a prefix (-include ...) file for clang completion."
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(interactive (let ((def (funcall company-clang-prefix-guesser)))
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(unless (stringp def)
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(setq def default-directory))
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(list (read-file-name "Prefix file: "
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(when def (file-name-directory def))
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def t (when def (file-name-nondirectory def))))))
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;; TODO: pre-compile?
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(setq company-clang--prefix (and (stringp prefix)
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(file-regular-p prefix)
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prefix)))
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;; Clean-up on exit.
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(add-hook 'kill-emacs-hook 'company-clang-set-prefix)
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;; parsing ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; TODO: Handle Pattern (syntactic hints would be neat).
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;; Do we ever see OVERLOAD (or OVERRIDE)?
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(defconst company-clang--completion-pattern
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"^COMPLETION: \\_<\\(%s[a-zA-Z0-9_:]*\\)\\(?: : \\(.*\\)$\\)?$")
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(defconst company-clang--error-buffer-name "*clang-error*")
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(defun company-clang--lang-option ()
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(if (eq major-mode 'objc-mode)
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(if (string= "m" (file-name-extension buffer-file-name))
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"objective-c" "objective-c++")
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(substring (symbol-name major-mode) 0 -5)))
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(defun company-clang--parse-output (prefix _objc)
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(goto-char (point-min))
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(let ((pattern (format company-clang--completion-pattern
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(regexp-quote prefix)))
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(case-fold-search nil)
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lines match)
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(while (re-search-forward pattern nil t)
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(setq match (match-string-no-properties 1))
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(unless (equal match "Pattern")
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(save-match-data
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(when (string-match ":" match)
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(setq match (substring match 0 (match-beginning 0)))))
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(let ((meta (match-string-no-properties 2)))
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(when (and meta (not (string= match meta)))
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(put-text-property 0 1 'meta
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(company-clang--strip-formatting meta)
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match)))
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(push match lines)))
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lines))
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(defun company-clang--meta (candidate)
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(get-text-property 0 'meta candidate))
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(defun company-clang--annotation (candidate)
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(let ((ann (company-clang--annotation-1 candidate)))
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(if (not (and ann (string-prefix-p "(*)" ann)))
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ann
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(with-temp-buffer
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(insert ann)
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(search-backward ")")
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(let ((pt (1+ (point))))
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(re-search-forward ".\\_>" nil t)
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(delete-region pt (point)))
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(buffer-string)))))
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(defun company-clang--annotation-1 (candidate)
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(let ((meta (company-clang--meta candidate)))
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(cond
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((null meta) nil)
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((string-match "[^:]:[^:]" meta)
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(substring meta (1+ (match-beginning 0))))
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((string-match "(anonymous)" meta) nil)
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((string-match "\\((.*)[ a-z]*\\'\\)" meta)
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(let ((paren (match-beginning 1)))
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(if (not (eq (aref meta (1- paren)) ?>))
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(match-string 1 meta)
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(with-temp-buffer
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(insert meta)
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(goto-char paren)
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(substring meta (1- (search-backward "<"))))))))))
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(defun company-clang--strip-formatting (text)
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(replace-regexp-in-string
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"#]" " "
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(replace-regexp-in-string "[<{[]#\\|#[>}]" "" text t)
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t))
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(defun company-clang--handle-error (res args)
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(goto-char (point-min))
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(let* ((buf (get-buffer-create company-clang--error-buffer-name))
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(cmd (concat company-clang-executable " " (mapconcat 'identity args " ")))
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(pattern (format company-clang--completion-pattern ""))
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(message-truncate-lines t)
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(err (if (re-search-forward pattern nil t)
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(buffer-substring-no-properties (point-min)
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(1- (match-beginning 0)))
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;; Warn the user more aggressively if no match was found.
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(message "clang failed with error %d: %s" res cmd)
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(buffer-string))))
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(with-current-buffer buf
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(let ((inhibit-read-only t))
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(erase-buffer)
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(insert (current-time-string)
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(format "\nclang failed with error %d:\n" res)
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cmd "\n\n")
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(insert err)
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(setq buffer-read-only t)
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(goto-char (point-min))))))
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(defun company-clang--start-process (prefix callback &rest args)
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(let* ((objc (derived-mode-p 'objc-mode))
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(buf (get-buffer-create "*clang-output*"))
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;; Looks unnecessary in Emacs 25.1 and later.
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(process-adaptive-read-buffering nil)
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(existing-process (get-buffer-process buf)))
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(when existing-process
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(kill-process existing-process))
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(with-current-buffer buf
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(erase-buffer)
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(setq buffer-undo-list t))
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(let* ((process-connection-type nil)
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(process (apply #'start-file-process "company-clang" buf
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company-clang-executable args)))
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(set-process-sentinel
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process
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(lambda (proc status)
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(unless (string-match-p "hangup\\|killed" status)
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(funcall
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callback
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(let ((res (process-exit-status proc)))
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(with-current-buffer buf
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(unless (eq 0 res)
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(company-clang--handle-error res args))
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;; Still try to get any useful input.
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(company-clang--parse-output prefix objc)))))))
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(unless (company-clang--auto-save-p)
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(send-region process (point-min) (point-max))
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(send-string process "\n")
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(process-send-eof process)))))
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(defsubst company-clang--build-location (pos)
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(save-excursion
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(goto-char pos)
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(format "%s:%d:%d"
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(if (company-clang--auto-save-p) buffer-file-name "-")
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(line-number-at-pos)
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(1+ (length
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(encode-coding-region
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(line-beginning-position)
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(point)
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'utf-8
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t))))))
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(defsubst company-clang--build-complete-args (pos)
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(append '("-fsyntax-only" "-Xclang" "-code-completion-macros")
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(unless (company-clang--auto-save-p)
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(list "-x" (company-clang--lang-option)))
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company-clang-arguments
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(when (stringp company-clang--prefix)
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(list "-include" (expand-file-name company-clang--prefix)))
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(list "-Xclang" (format "-code-completion-at=%s"
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(company-clang--build-location pos)))
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(list (if (company-clang--auto-save-p) buffer-file-name "-"))))
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(defun company-clang--candidates (prefix callback)
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(and (company-clang--auto-save-p)
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(buffer-modified-p)
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(basic-save-buffer))
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(when (null company-clang--prefix)
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(company-clang-set-prefix (or (funcall company-clang-prefix-guesser)
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'none)))
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(apply 'company-clang--start-process
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prefix
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callback
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(company-clang--build-complete-args
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(if (company-clang--check-version 4.0 9.0)
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(point)
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(- (point) (length prefix))))))
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(defun company-clang--prefix ()
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(if company-clang-begin-after-member-access
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(company-grab-symbol-cons "\\.\\|->\\|::" 2)
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(company-grab-symbol)))
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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(defconst company-clang-required-version 1.1)
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(defvar company-clang--version nil)
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(defun company-clang--auto-save-p ()
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(not
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(company-clang--check-version 2.9 3.1)))
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(defun company-clang--check-version (min apple-min)
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(pcase company-clang--version
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(`(apple . ,ver) (>= ver apple-min))
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(`(normal . ,ver) (>= ver min))
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(_ (error "pcase-exhaustive is not in Emacs 24.3!"))))
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(defsubst company-clang-version ()
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"Return the version of `company-clang-executable'."
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(with-temp-buffer
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(call-process company-clang-executable nil t nil "--version")
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(goto-char (point-min))
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(if (re-search-forward "\\(clang\\|Apple LLVM\\) version \\([0-9.]+\\)" nil t)
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(cons
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(if (equal (match-string-no-properties 1) "Apple LLVM")
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'apple
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'normal)
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(string-to-number (match-string-no-properties 2)))
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0)))
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(defun company-clang (command &optional arg &rest ignored)
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"`company-mode' completion backend for Clang.
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Clang is a parser for C and ObjC. Clang version 1.1 or newer is required.
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Additional command line arguments can be specified in
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`company-clang-arguments'. Prefix files (-include ...) can be selected
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with `company-clang-set-prefix' or automatically through a custom
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`company-clang-prefix-guesser'.
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With Clang versions before 2.9, we have to save the buffer before
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performing completion. With Clang 2.9 and later, buffer contents are
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passed via standard input."
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(interactive (list 'interactive))
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(cl-case command
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(interactive (company-begin-backend 'company-clang))
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(init (when (memq major-mode company-clang-modes)
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(unless company-clang-executable
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(error "Company found no clang executable"))
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(setq company-clang--version (company-clang-version))
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(unless (company-clang--check-version
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company-clang-required-version
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company-clang-required-version)
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(error "Company requires clang version %s"
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company-clang-required-version))))
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(prefix (and (memq major-mode company-clang-modes)
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buffer-file-name
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company-clang-executable
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(not (company-in-string-or-comment))
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(or (company-clang--prefix) 'stop)))
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(candidates (cons :async
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(lambda (cb) (company-clang--candidates arg cb))))
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(meta (company-clang--meta arg))
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(annotation (company-clang--annotation arg))
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(post-completion (let ((anno (company-clang--annotation arg)))
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(when (and company-clang-insert-arguments anno)
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(insert anno)
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(if (string-match "\\`:[^:]" anno)
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(company-template-objc-templatify anno)
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(company-template-c-like-templatify
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(concat arg anno))))))))
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(provide 'company-clang)
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;;; company-clang.el ends here
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